1. Field of the Invention
This invention relates to weirs and particularly to weirs for pickling and cleaning systems. More particularly, the invention relates to a pressurized weir for use in a closed cell pickling or cleaning system and which provides a water curtain of an adjustable thickness which makes the system essentially fumeless.
2. Description of the Prior Art
Heretofore, the fume problems associated with pickling and cleaning tanks which include acids have been addressed by closing the tanks with covers, utilizing exhaust fans or providing weirs over which water overflows or cascades to prevent fume emissions from escaping the tanks. Prior art gravity weir designs have, however, been characterized by unpredictable, uncontrollable and unreliable overflow and cascading weir designs. Prior weir designs also were characterized by a lack of water curtain uniformity and the presence of a water necking problem which caused the water curtain to have non-uniform thickness and be marked by discontinuities which rendered the curtain pervious to fume exhaust.